The present subject matter relates to atmospheric pressure plasma apparatus, and more particularly to an atmospheric pressure plasma apparatus for enhancing dissolvability of a secondary gas by converting a source gas into a plasma state in an atmospheric state and passing a secondary gas through a path isolated from a region where plasma is generated.
Plasma is generally defined as a state of matter composed of ions, electrons, radicals, and a variety of neutral species, by an electric field, to be in an electrically neutral state. Such plasma is widely used in numerous applications such as modifying surface properties of materials, etching, coating, sterilization, disinfecting, generating ozone, dyeing, cleaning waste water, cleaning faucet water, air cleaning, and high-gain lamps, and so forth employing ions, electrons, and radicals therein.
Plasma is classified into low-pressure plasma (several mm Torr to several Torr) and high-pressure plasma (several Torr to 760 Torr), depending on the pressure created. Low pressure plasma is easily generated, but shows several disadvantages. For example, since vacuum chambers and exhaust apparatus are required to maintain a low state, low plasma suffers from the disadvantage of high expense. In addition, it is difficult to produce low pressure plasma on a large scale by adopting batch type.
On the other hand, high-pressure plasma is created in atmospheric pressure (760 Torr). As a result, expensive vacuum systems are not required, and it is possible to produce high-pressure plasma on a large scale by employing continuous process.
Meanwhile, when high voltage is applied to two separated electrodes and source gas is supplied therebetween, the source gas becomes ionized and dissolved to generate plasma.
In the event that a secondary gas is supplied to a region where the plasma is generated, it collides with particles such as ions, electrons, and radicals, which are formed by dissolving the source gas, so that the molecular combination of the secondary gas becomes disconnected to ionize molecules. Accordingly, the atmospheric pressure plasma apparatus are now applied employing ionized source gas to a broad range of fields, including processing such as modifying surface properties, etching, deposition, nanotube-growth, and so forth.
In conventional atmospheric pressure plasma apparatuses, however, the source gas is converted into plasma in a region where plasma is generated between two electrodes. Then, the secondary gas is ionized in the region where plasma is generated, which is to be injected to outside via one of two electrodes. As a result, dissolved secondary gas collides against a path capable of passing one of two electrodes. For this reason, the conventional atmospheric apparatus, however, have the drawback in which the reagent of the dissolved secondary gas is lost.
In other words, after the source gas is provided to a region where plasma is created to be dissolved, it is injected to the outside. Thus, there is a disadvantage that the reagent of the secondary gas is dissolved under injection process.